Question

(x-5)(x+5)-(x+3)^2=(x+1)^2-(x+4)(x-4)
tìm x

Answer 1

\(\left(x-5\right)\left(x+5\right)-\left(x+3\right)^2=\left(x+1\right)^2-\left(x+4\right)\left(x-4\right)\)

\(\Leftrightarrow x^2-25-x^2-6x-9=x^2-2x+1-x^2+16\)

\(\Leftrightarrow-4x=51\)

\(\Leftrightarrow x=-\dfrac{51}{4}\)

Answer 2

`(x - 5)(x + 5) - (x + 3)^2 = (x + 1)^2 - (x + 4)(x - 4)`

`x^2 - 25 - (x^2 + 6x+ 9) = x^2 + 2x + 1 - (x^2 - 16)`

`x^2 - 25 - x^2 - 6x - 9 = x^2 + 2x + 1 - x^2 + 16`

`-6x - 34 = 2x + 17`

`-6x - 2x = 17 + 34`

`-8x = 51`

`x = -51/8`

Vậy: `x = -51/8`